CN102985266B - For the crown reinforcement of aircraft tyre - Google Patents

Abstract

The present invention relates to an improvement in moving the heat generated in the working reinforcement of an aircraft tire from the hottest point, usually at the end of the working reinforcement layer, to the least hot spot The point is usually located in the middle area of the working reinforcement, resulting in a more even temperature distribution within the crown of the tire. An aircraft tire comprising: a crown reinforced by a working reinforcement (3) comprising at least one working reinforcement layer (30), said working reinforcement layer (30 ) is made of axially juxtaposed substantially circumferential belts (31) made of mutually parallel textile reinforcement elements (32) coated with a polymeric coating material (33) production. According to the invention, each belt is in contact at least on its radially inner axial face with a heat transfer element (34), said heat transfer element (34) comprising at least one heat-conducting material, the thermal conductivity of the heat-conducting material of the heat transfer element at least equal to 50 times the thermal conductivity of the polymer coating material of the textile reinforcing element of the belt in contact with the heat transfer element, the product of the thickness of the heat transfer element times the tensile modulus of the heat transfer element is at most equal to 0.3 times the product of the thickness of the belt times the tensile modulus of the belt.

Description

Crown reinforcements for aircraft tires

technical field

The present invention relates to aircraft tires and, more particularly, to crown reinforcements for aircraft tires comprising a layer of textile reinforcing elements.

Background technique

Since the geometry of the tire exhibits rotational symmetry about the axis of rotation, the geometry of the tire can be described as a meridian plane that includes the axis of rotation of the tire. For a given meridian plane, radial, axial and circumferential directions denote directions perpendicular to the axis of rotation of the tire, parallel to the axis of rotation of the tire and perpendicular to the meridian plane, respectively. Hereinafter, the expressions "radially inner" and "radially outer" mean "closer in the radial direction to the rotation axis of the tire" and "farther in the radial direction from the rotation axis of the tire", respectively. The expressions "axially on the inside" and "axially on the outside" mean "in the axial direction close to the equatorial plane" and "in the axial direction away from the equatorial plane", the equatorial plane being perpendicular to the rotation of the tire axis and passes through the center of the tire tread surface.

Aircraft tires are characterized by a nominal pressure in excess of 9 bar and a nominal deflection level greater than or equal to 32%. The nominal pressure is, for example, the nominal inflation pressure of the tire defined by a standard established by the Tire and Rim Association or TRA. By definition, the nominal deflection level of a tire is the radial deformation, or radial height, of the tire as it changes from an unloaded inflated state to a statically loaded inflated state under nominal load and pressure conditions such as those defined by the TRA standard The change. The nominal deflection level is expressed in terms of relative deflection and is defined as the ratio of the change in tire radial height to half the difference between the tire outside diameter and the largest diameter of the rim measured at the rim. The outside diameter of the tire is measured under static conditions in the unloaded state inflated to the nominal pressure.

A tire generally comprises: a crown, which includes a tread, which is intended to come into contact with the ground through the tread surface; two beads, which are intended to come into contact with the rim; and two sidewalls, The sidewalls connect the crown to the beads. Radial tires such as those commonly used for aircraft more particularly comprise radial carcass reinforcements and crown reinforcements such as described in document EP1381525.

The radial carcass reinforcement is the tire reinforcement structure that connects the two beads of the tire. The radial carcass reinforcement of an aircraft tire generally comprises at least one carcass reinforcement layer, each made of mutually parallel reinforcing elements, usually fabrics, forming an angle of 80° to the circumferential direction Angles between and 100°.

The crown reinforcement is a tire reinforcement structure located radially on the inside of the tread and at least partially radially on the outside of the radial carcass reinforcement. The crown reinforcement of an aircraft tire generally comprises at least one crown reinforcement layer, each made of mutually parallel reinforcing elements coated with a polymeric coating material. Within the crown reinforcement layer, a distinction is made between the layer of working reinforcement, which constitutes the working reinforcement and is usually made of textile reinforcing elements, and the layer of protective reinforcement, which constitutes the protective reinforcement. The reinforcement is also made of metal or textile reinforcement elements radially external to the working reinforcement.

During the manufacture of aircraft tires, the layers of working reinforcement are usually formed by zigzag or sequential winding of a belt made of textile reinforcing elements around a cylindrical manufacturing device, with axial translational movement of the belt with each winding, The desired axial width of the layer of working reinforcement is thereby obtained. Thus, the layers of working reinforcements are made of belts juxtaposed in the axial direction. Zigzag winding means winding in a curve formed by periodic corrugations on half the period of each winding or on one period of each winding, the angle of the fabric reinforcing elements of the belt with respect to the circumferential direction is usually between 8° and between 30°. For working reinforcement layers formed by successive windings, the angle of the textile reinforcing elements of the belt with respect to the circumferential direction is generally between 0° and 8°. Regardless of the type of winding of the belt, the angle of the textile reinforcing elements of the belt with respect to the circumferential direction is generally less than 30°. For this reason, the belt and the formed working layer are said to be substantially circumferential, which means that the direction along the corrugations of limited amplitude around the circumferential direction is substantially circumferential.

The reinforcing elements of the working reinforcement layer are parallel to each other, which means that the distance between the geometric curves of two adjacent reinforcing elements is constant, the geometric curves possibly exhibiting periodic corrugations.

For aircraft tyres, the reinforcing elements of the carcass reinforcement layer and of the working reinforcement layer are generally cords made of spinning of textile filaments, preferably of aliphatic or aromatic polyamides. The reinforcing elements protecting the reinforcement layer can be cords made of metallic threads or cords made of spun yarns of textile threads.

The mechanical properties in tension (modulus, elongation at break and force at break) of the textile reinforcing elements were measured after preconditioning. "Pre-conditioning" means that the textile reinforcing elements have been stored for at least 24 hours in a standard atmosphere according to European standard DIN EN 20139 (temperature of 20 ± 2°C; relative humidity of 65 ± 2%) before measurement. The measurement is carried out in a known manner using a tensile testing machine type 1435 or 1445 manufactured by ZWICK GmbH & Co (Germany). The textile reinforcing elements were subjected to stretching at a nominal speed of 200 mm/min over an initial length of 400 mm. All results are averaged over 10 measurements.

The polymer material used for the textile reinforcement elements of the working reinforcement layer, such as the polymer coating material, is mechanically characterized after curing by means of tensile stress-strain properties determined by tensile tests. Using methods known to those skilled in the art (e.g. according to International Standard ISO37) and under conditions of nominal temperature (23+ or -2°C) and humidity (50+ or -5% relative humidity) as defined by International Standard ISO471 The tensile test is carried out on the specimen. For polymer blends, the tensile stress measured for 10% elongation of the specimen is considered the modulus of elasticity or tensile modulus at 10% elongation and is expressed in megapascals (MPa).

In use, running mechanical stresses from the combined action of nominal pressure, load applied to the tires (which may vary between 0 and 2 times nominal load) and speed of the aircraft in the working reinforcement layer Stretch loops are created in the reinforcing elements.

These stretching cycles generate heat sources within the working reinforcement layer, in particular the polymer coating material of the reinforcing elements at the axial ends of the working reinforcement layer. These heat sources are located at hot spots where heat removal is difficult because the heat must be able to travel through the polymer coating material or through the textile reinforcement elements. However, polymer coating materials are poor thermal conductors due to their low thermal conductivity. Likewise, textile reinforcement elements do not effectively contribute to heat removal due to their low thermal conductivity. This causes the polymer coating material to overheat, which is detrimental to its proper mechanical integrity and potentially breaks it down, causing premature tire failure.

Various technical solutions have been conceived in an attempt to create a means for removing the heat generated in the working reinforcement. Documents EP1031441 and JP2007131282 disclose thermally conductive polymer materials with improved thermal conductivity. Document EP1548057 proposes polymer materials comprising carbon nanotubes to increase thermal conductivity. Document EP1483122 describes heat removal elements in the form of metal cables laid in the meridian plane and inserted at the ends of the working reinforcement. Finally, document KR812810 proposes thermally conductive inserts, which may be metallic and arranged at the ends of the working reinforcement.

Contents of the invention

The object the inventors of the present application have set themselves is to improve the movement of the heat generated in the working reinforcement of an aircraft tire from the hottest point, which is usually located at the layer of the working reinforcement, to the least hot point At the ends, said least hot spot is generally located in the middle area of the working reinforcement, so as to obtain a more uniform temperature distribution within the crown of the tire while minimizing its influence on the mechanical loading of the working reinforcement.

According to the invention, this object is achieved using an aircraft tire comprising:

- a crown intended to be in contact with the ground through the tread and connected by two sidewalls to two beads intended to be in contact with the rim,

- a radial carcass reinforcement connecting said two beads,

- a crown reinforcement radially inside said tread and radially outside said radial carcass reinforcement, said crown reinforcement comprising working reinforcements and protective reinforcements,

- said working reinforcement is located radially inside said protective reinforcement and comprises at least one layer of working reinforcement,

- each layer of the working reinforcement consists of substantially circumferential belts juxtaposed axially,

- each belt is made of mutually parallel textile reinforcing elements coated with a polymer coating material,

- each belt of at least one layer of working reinforcement is in contact at least on its radially inner axial face with a heat transfer element comprising at least one heat conducting material,

- the thermal conductivity of the thermally conductive material of the heat transfer element is at least equal to 50 times the thermal conductivity of the polymer coating material of the textile reinforcing element of the belt in contact with the heat transfer element,

- the product of the thickness of the heat transfer element multiplied by the tensile modulus of the heat transfer element is at most equal to 0.3 times the product of the thickness of the belt multiplied by the tensile modulus of the belt.

According to the invention, each belt of at least one layer of working reinforcement is advantageously in contact with the heat transfer element at least on its radially inner axial face, meaning that the belt is parallel to the axis of rotation of the tire and The face radially closest to the tire's axis of rotation.

The heat transfer element performs the function of removing heat due to the presence of at least one heat conducting material. The heat transfer element does not have to be made of only heat conducting material.

The thermally conductive material means a material with a high thermal conductivity, such as a metal material. The thermal conductivity of a material is a physical quantity that characterizes the ability of a material to carry heat energy, expressed in Wm ^-1 .K ^-1 . The higher the thermal conductivity of a thermally conductive material, the better it is at transferring thermal energy.

In contrast, a material that is not a heat conductor or more precisely a poor heat conductor means a material with a low thermal conductivity, such as conventional polymer materials conventionally used in tires.

The heat or thermal energy generated at the axial ends of the layers of working reinforcement is removed by heat transfer elements in contact with the belts located at the axial ends of the layers of working reinforcement, and then axially inwards Progressive transfer to the heat transfer element in contact with the axially innermost and axially juxtaposed belt. Since the belt is oriented substantially in the circumferential direction, the corresponding heat transfer elements in contact with said belt will distribute the heat generated at the axial ends of the layers of working reinforcement in the circumferential direction. Thus, the heat generated at the axial ends of the layers of working reinforcement is removed axially and circumferentially by means of heat transfer elements respectively in contact with the juxtaposed belts, so that over the axial width of the layer of working reinforcement , between its axial ends and its mid-section, and around the working reinforcement layer to equalize the temperature.

Said heat transfer is made possible due to the higher temperature between the axial ends and the middle of the layer of working reinforcement, creating a temperature gradient that promotes heat conduction, the purpose of which is to make the layer of working reinforcement The temperature is uniform between the axial ends and the middle.

In order to remove thermal energy preferably through the heat transfer element which is in contact with the belt constituting the layer of working reinforcement, the thermal conductivity of the heat transfer material of the heat transfer element needs to be significantly higher than that of the tape used to coat the heat transfer element in contact with the heat transfer element. The thermal conductivity of the polymer coating material of the textile reinforcing elements of the bundle, which by nature is a poor thermal conductor. The inventors of the present application have demonstrated that removal is permitted when the thermal conductivity of the thermally conductive material is at least equal to 50 times the thermal conductivity of the polymeric coating material used to coat the textile reinforcing elements of the belt in contact with the heat transfer element A sufficient amount of thermal energy such that the heat level at the axial ends of the layer of working reinforcement can be reduced to an acceptable level, ie a level that does not decompose the relevant material.

Again according to the invention, the product of the thickness of the heat transfer element multiplied by the tensile modulus of the heat transfer element is at most equal to 0.3 times the product of the thickness of the belt multiplied by the tensile modulus of the belt.

Tensile modulus is defined as the slope of a line tangent to the tensile curve, defining tensile force as a function of elongation at the point on the tensile curve corresponding to a tensile force of 50 daN.

This feature makes it possible to limit the contribution of the heat transfer element to the overall circumferential tensile stiffness of the belt and heat transfer element assembly. In other words, the presence of the heat transfer element has limited influence on the mechanical stresses the belt is subjected to.

Specifically, the product of thickness, tensile modulus and elongation of the belt is calculated to give the hoop load per unit axial width of the belt. Similarly, the product of the thickness, tensile modulus and elongation of the heat transfer element is calculated to give the hoop load per unit axial width of the heat transfer element. Since the elongation of the belt and the heat transfer element are the same, this means that the circumferential load (or distributed tension) per unit axial width of the heat transfer element is thus at most equal to the per unit axial force of the belt in contact with the heat transfer element 0.3 times the width of the circumferential load. In other words, under the applied circumferential load, the mechanical contribution produced by the heat transfer element thus remains limited to 30% of that of the belt.

Advantageously, each belt of each layer of working reinforcement is in contact at least on its radially inner axial face with a heat transfer element comprising at least one heat conducting material. The heat generated at the axial ends of each layer of working reinforcement (not only at the axial end with the highest temperature) is advantageously removed so that in each layer of working reinforcement and thus Uniform temperature throughout the thickness of the radial reinforcement.

Also advantageously, the heat transfer element is made of at least one substantially circumferential band. The metal strip is an element extending around the entire periphery of the belt and has a rectangular meridional cross-section with the shortest dimension in the meridional plane oriented radially and the longest dimension in the meridian plane oriented axially. The metal strap is made of metal material. The substantially circumferential belt follows the substantially circumferential path of the belt in contact with it.

A first preferred embodiment has a heat transfer element made of a single substantially circumferential metal strip having an axial width equal to the axial width of the belt in contact with the heat transfer element . In this embodiment, the axial width of the single substantially circumferential metal strip is equal to the axial width of the belt, which is advantageous in tire manufacturing because the belt and the single substantially circumferential metal strip can Pre-assembled at the base level, the resulting assembly of belts and single substantially circumferential metal strips can then be wound on cylindrical equipment for forming layers of working reinforcement. Furthermore, thermal conductivity continuity in circumferential and axial directions is provided by the continuity of each individual substantially circumferential metal strip and by the helical or zigzag circumferential winding of the strips. This embodiment thus allows optimal removal of the heat generated at the ends of the layers of working reinforcement in both axial and circumferential directions.

According to a second embodiment of the invention, the heat transfer element is made of a plurality of axially juxtaposed substantially circumferential metal strips, the axial The sum of the widths is at most equal to the axial width of the belt in contact with said heat transfer element. This embodiment is comparable in terms of heat conduction to the above-described embodiment with a single substantially circumferential metal strip. Furthermore, the juxtaposition of substantially circumferential metal strip elements advantageously presents a lower bending stiffness about the radial direction of a single substantially circumferential metal strip, which means that it contributes less to the bending stiffness of the belt about the radial direction. Small effect, and thus on the bending stiffness of the working reinforcement layer about the radial direction: the introduction of the heat transfer element therefore has a small effect on the mechanical properties of the working reinforcement.

A third embodiment of the present invention is characterized by a heat transfer element made of a plurality of axially disjoint substantially circumferential metal strips that The belt is distributed over the axial width of the belt in contact with the heat transfer element. In this embodiment, the heat transfer element is thus made of a plurality of substantially circumferential metal strips which do not intersect each other two by two in the axial direction: this means that the substantially circumferential The sum of the axial widths of the metal strips is smaller than the axial width of the strips in contact with the substantially circumferential metal strips. Due to this geometrical discontinuity between the substantially circumferential metal strips, the heat conduction is discontinuous in the axial direction and continuous in the circumferential direction. However, such an embodiment makes it possible for a heat transfer element made of disjoint substantially circumferential metal strips to have a lower stiffness than a heat transfer element made of a single substantially circumferential metal strip. As in the second embodiment, the bending stiffness in the radial direction of the plurality of substantially circumferential metal strips that do not intersect each other two by two is lower than the bending stiffness in the radial direction of a single substantially circumferential metal strip. Furthermore, the circumferential tensile stiffness of the heat transfer elements in this embodiment contributes only a small amount to the circumferential tensile stiffness of the belt and heat transfer element assembly, and this allows for a more An assembly of tape and heat transfer elements that is easily wound around a cylindrical device.

According to an optional feature of the invention, the substantially circumferential metal strip advantageously comprises holes. Whether the heat transfer element is made of a single substantially cylindrical metal strip or a plurality of axially juxtaposed or non-intersecting substantially circumferential metal strips, the holes piercing each substantially circumferential metal strip make The direct contact between the respective polymer coating materials of the two belts via the holes promotes better adhesion between the two belts radially outside and radially inside the metal strip, respectively.

According to another optional feature of the invention, the substantially circumferential metal strip includes circular holes. In addition to the advantages already mentioned with regard to the circumferential tensile stiffness of the assembly of belt and heat transfer element, the formation of circular holes, eg by perforation, is simple from an industrial point of view.

The substantially circumferential metal strip advantageously comprises holes with a diameter at most equal to half the axial width of the strip, since the cross-section of the holes in the metal strip must be limited in order to be effective in conducting heat.

The thermally conductive material of the heat transfer element is still more advantageously metal. Metallic materials, such as aluminum, have a thermal conductivity of about 200 W.m ^-1 .K ^-1 , while polymeric materials have a thermal conductivity of about 0.3 Wm ^-1 .K ^-1 .

Preferably, the thermally conductive material of the heat transfer element is aluminum characterized by high thermal conductivity and low density. Aluminum requires an interfacial coating so that it adheres to the polymer coating material of the contacting belt; various techniques exist for this purpose: brass-type coatings, organic-type (silane or aminosilane) coatings, Epoxy or commercially available adhesives.

A heat transfer element made of one or several substantially circumferential aluminum metal strips advantageously has a constant thickness at most equal to 0.1 mm, thereby limiting the circumferential tensile stiffness of the heat transfer element.

Finally, it is advantageous for any heat transfer element to have, around its entire circumference, a periodic geometrical oscillation in a circumferential plane perpendicular to the axial direction. These periodic geometric oscillations may, without being exhaustive, be alternating V-shaped bends or sinusoidal type corrugations. The presence of periodic geometric oscillations increases the circumferential ductility of the heat transfer element and thus reduces the risk of the heat transfer element being snapped.

Advantageously, the ratio between the peak-to-peak amplitude of the periodic geometric oscillations and the periodic wavelength is greater than 0.05, thereby imparting satisfactory circumferential extensibility to the heat transfer element.

Another subject of the invention is a metallized belt comprising:

- a belt made of mutually parallel textile reinforcing elements coated with a polymeric coating material,

- said belt is in contact at least on its radially inner axial face with a heat transfer element comprising at least one heat conducting material,

- the thermal conductivity of the thermally conductive material of the heat transfer element is at least equal to 50 times the thermal conductivity of the polymer coating material of the textile reinforcing element of said belt in contact with the heat transfer element,

- and the product of the thickness of the heat transfer element multiplied by the tensile modulus of the heat transfer element is at most equal to 0.3 times the product of the thickness of the belt multiplied by the tensile modulus of the belt.

The invention also relates to the use of the metallized belt described above in a tire according to the invention.

Another subject of the invention is a metallized belt for a tire according to the invention exhibiting all the above-mentioned characteristics.

Description of drawings

The features and other advantages of the present invention will be better understood with the help of accompanying drawings 1 to 5:

- Figure 1 has a meridional cross-section of the crown of a tire according to the invention, particularly schematically showing the belts of working reinforcement layers and the corresponding substantially circumferential belts of heat transfer elements.

- Figure 2 is a diagram of an assembly of belts and heat transfer elements of a working reinforcement layer according to a first embodiment of the invention.

- Figure 3 is a diagram of an assembly of belts and heat transfer elements of a working reinforcement layer according to a second embodiment of the invention.

- Figure 4 is a diagram of an assembly of belts and heat transfer elements of a working reinforcement layer according to a third embodiment of the invention.

- Figure 5 is a diagram of an alternative form of the heat transfer element.

In order to facilitate the understanding of the present invention, Figures 1 to 5 are not necessarily drawn to scale.

Detailed ways

Figure 1 shows a meridian cross-section, ie a cross-section in a meridian plane, of the crown of a tire according to the invention. It depicts the crown intended to come into contact with the ground through the tread 1, the radial carcass reinforcement 2, the crown reinforcement radially inside the tread and radially outside the radial carcass reinforcement, Said crown reinforcement comprises a working reinforcement 3 and a protective reinforcement 4 . The working reinforcements 3 made of overlapping working reinforcement layers are not all shown: only one working reinforcement layer 30 has been shown in order to make the invention easier to understand. The layer of working reinforcements is made of substantially circumferential belts 31 juxtaposed axially. Each belt is made of mutually parallel textile reinforcement elements 32 coated with a polymeric coating material 33 . Each belt is in contact with the heat transfer element 34 on its radially inner axial face.

Figure 2 is a diagram of an assembly of belts 231 and heat transfer elements 234 of a working reinforcement layer according to a first embodiment of the invention. a belt made of mutually parallel textile reinforcing elements 232 coated with a polymeric coating material 233 is in contact on its radially inner axial face with a heat transfer element 234 made of a single substantially circumferential metal strip, The axial width of the single substantially circumferential metal strip is equal to the axial width of the belt 231 in contact.

Figure 3 is a diagram of an assembly of belts 331 and heat transfer elements 334 of a working reinforcement layer according to a second embodiment of the invention. A belt 331 made of mutually parallel textile reinforcing elements 332 coated with a polymer coating material 333 is formed on its radially inner axial face with a plurality of axially juxtaposed substantially circumferential metal strips The heat transfer element 334 is in contact, and the total axial width of the plurality of axially juxtaposed substantially circumferential metal strips (that is, the sum of the axial widths of each substantially circumferential metal strip) is equal to the contacting The axial width of the belt 331.

Figure 4 is a diagram of an assembly of belts 431 and heat transfer elements 434 of a working reinforcement layer according to a third embodiment of the invention. A belt made of mutually parallel textile reinforcing elements 432 coated with a polymer coating material 433 is formed on its radially inner axial face from a plurality of axially non-intersecting substantially circumferential metal strips The heat transfer elements 434 are in contact with each other, and the plurality of axially non-intersecting substantially circumferential metal strips are distributed over the axial width of the contacting strips 431 .

Finally, FIG. 5 depicts a heat transfer element 234 made of a single substantially circumferential metal strip comprising circular holes 235 .

The inventors of the present application carried out the invention according to its first embodiment on an aircraft tire of size 46x17R20, using which is characterized by a nominal pressure of 15.9 bar, a nominal static load of 20473 daN and a maximum reference of 225 km/h speed. The working crown reinforcement of the tire consists of 9 working reinforcement layers made of substantially circumferential belts, 3 of which are laid side by side in the axial direction, and 6 of which are wound in each turn as a cycle. Zigzag-wound, the maximum angle of the textile reinforcing elements of the belt with respect to the circumferential direction is equal to 11°. Each belt is made of hybrid reinforcement elements coated with a polymer coating material with a thermal conductivity equal to 0.3 Wm ^{-1 .K -1 ,} that is, from spinning of aramid filaments and aliphatic polyamide filaments Made from a combination of spinning yarns. Each substantially circumferential belt is in contact on its radially inner face with a heat transfer element made of an aluminum metal strip with a thickness of 0.02 mm and a thermal conductivity of 237 W.m ^-1 .K ^-1 become. The thermal conductivity of the aluminum from which the heat transfer element is made is approximately 600 times that of the polymer coating material of the textile reinforcing element of the belt in contact with the heat transfer element.

The inventors of the present application carried out finite element numerical simulations on a tire running steadily at a speed of 10 km/h under a nominal static load of 20.5 tons and a nominal pressure of 15.9 bar, thereby demonstrating that when starting from a reference tire (with no heat transfer elements) to the tire according to the invention, near the equatorial plane, the temperature difference between the axial ends and the middle part of the most thermally loaded layer of working reinforcement drops from 90.5°C to 78.5°C . In the chosen example, the invention therefore enables a maximum temperature drop of 12°C at the ends of the crown reinforcement.

Claims (10)

1. An aircraft tire, comprising: - a crown intended to be in contact with the ground through the tread (1) and connected by two sidewalls to two beads intended to be in contact with the rim, - a radial carcass reinforcement (2) connecting said two beads, - a crown reinforcement radially inside said tread and radially outside said radial carcass reinforcement, said crown reinforcement comprising working reinforcements (3 ) and protective reinforcements (4), - said working reinforcement is located radially inside said protective reinforcement and comprises at least one working reinforcement layer (30), - each layer of the working reinforcement consists of axially juxtaposed substantially circumferential belts (31, 231, 331, 431), - each belt is made of mutually parallel textile reinforcing elements (32, 232, 332, 432) coated with a polymeric coating material (33, 233, 333, 433), It is characterized in that each belt of at least one working reinforcement layer is in contact at least on its radially inner axial face with a heat transfer element (34, 234, 334, 434), said heat transfer element (34, 234, 334, 434) comprising at least one thermally conductive material, the thermally conductive material of the heat transfer element having a thermal conductivity at least equal to 50 times the thermal conductivity of the polymer coating material of the textile reinforcing element of the belt in contact with the heat transfer element, and the product of the thickness of the heat transfer element times the tensile modulus of the heat transfer element is at most equal to 0.3 times the product of the thickness of the belt times the tensile modulus of the belt, and The heat transfer element is made from a single substantially circumferential metal strip (34, 234) having an axial width equal to that of the strip in contact with the heat transfer element Axial width of bundle (31, 231). 2. An aircraft tire, comprising: - a crown intended to be in contact with the ground through the tread (1) and connected by two sidewalls to two beads intended to be in contact with the rim, - a radial carcass reinforcement (2) connecting said two beads, - a crown reinforcement radially inside said tread and radially outside said radial carcass reinforcement, said crown reinforcement comprising working reinforcements (3 ) and protective reinforcements (4), - said working reinforcement is located radially inside said protective reinforcement and comprises at least one working reinforcement layer (30), - each layer of the working reinforcement consists of axially juxtaposed substantially circumferential belts (31, 231, 331, 431), - each belt is made of mutually parallel textile reinforcing elements (32, 232, 332, 432) coated with a polymeric coating material (33, 233, 333, 433), It is characterized in that each belt of at least one working reinforcement layer is in contact at least on its radially inner axial face with a heat transfer element (34, 234, 334, 434), said heat transfer element (34, 234, 334, 434) comprising at least one thermally conductive material, the thermally conductive material of the heat transfer element having a thermal conductivity at least equal to 50 times the thermal conductivity of the polymer coating material of the textile reinforcing element of the belt in contact with the heat transfer element, and the product of the thickness of the heat transfer element times the tensile modulus of the heat transfer element is at most equal to 0.3 times the product of the thickness of the belt times the tensile modulus of the belt, and The heat transfer element is made of a plurality of axially juxtaposed substantially circumferential metal strips (334), the sum of the axial widths of which is at most Equal to the axial width of the belt (331 ) in contact with the heat transfer element. 3. An aircraft tire, comprising: - a crown intended to be in contact with the ground through the tread (1) and connected by two sidewalls to two beads intended to be in contact with the rim, - a radial carcass reinforcement (2) connecting said two beads, - a crown reinforcement radially inside said tread and radially outside said radial carcass reinforcement, said crown reinforcement comprising working reinforcements (3 ) and protective reinforcements (4), - said working reinforcement is located radially inside said protective reinforcement and comprises at least one working reinforcement layer (30), - each layer of the working reinforcement consists of axially juxtaposed substantially circumferential belts (31, 231, 331, 431), - each belt is made of mutually parallel textile reinforcing elements (32, 232, 332, 432) coated with a polymeric coating material (33, 233, 333, 433), It is characterized in that each belt of at least one working reinforcement layer is in contact at least on its radially inner axial face with a heat transfer element (34, 234, 334, 434), said heat transfer element (34, 234, 334, 434) comprising at least one thermally conductive material, the thermally conductive material of the heat transfer element having a thermal conductivity at least equal to 50 times the thermal conductivity of the polymer coating material of the textile reinforcing element of the belt in contact with the heat transfer element, and the product of the thickness of the heat transfer element times the tensile modulus of the heat transfer element is at most equal to 0.3 times the product of the thickness of the belt times the tensile modulus of the belt, and The heat transfer element is made of a plurality of axially non-intersecting substantially circumferential metal strips (434) distributed between said The axial width of the belt (431) where the heat transfer element is in contact. 4. Tire according to any one of claims 1 to 3, characterized in that the substantially circumferential metal strip (34, 234, 334, 434) comprises holes (235). 5. Tire according to any one of claims 1 to 3, characterized in that the substantially circumferential metal strip (34, 234, 334, 434) comprises circular holes (235). 6. Tire according to any one of claims 1 to 3, characterized in that the substantially circumferential metal band (34, 234, 334, 434) comprises holes ( 235). 7. Tire according to any one of claims 1 to 3, characterized in that the thermally conductive material of the heat transfer element (34, 234, 334, 434) is made of metal. 8. Tire according to any one of claims 1 to 3, characterized in that the thermally conductive material of the heat transfer element (34, 234, 334, 434) is made of aluminium. 9. Tire according to claim 8, characterized in that the heat transfer element (34, 234, 334, 434) has a thickness at most equal to 0.1 mm. 10. Tire according to any one of claims 1 to 3, characterized in that any heat transfer element (34, 234, 334, 434) has a periodic geometrical oscillation in a circumferential plane perpendicular to the axial direction .